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A new study finds that high intakes of flavonols, antioxidants found in many vegetables, fruits, teas and wine, can slow the rate of memory loss.
Cognitive scores in those who consumed the most flavonols in the study declined 0.4 units per decade slower than those who consumed the least flavonols. The results were maintained even after adjusting for other possible factors. recently published research In Neurology, the medical journal of the American Academy of Neurology.
“It’s very interesting that our study shows that certain dietary choices can slow the rate of cognitive decline,” said the study’s author, a doctor of medicine. Instructor Dr. Thomas Holland said: In a statement at Rush University Medical Center in Chicago.
“The simple things of eating more fruits and vegetables and drinking more tea are simple ways for people to play an active role in maintaining brain health.”
Because flavonols are cytoprotective, meaning they protect cells, including neurons, they can have a direct impact on cognition, says David Katz, M.D., an expert in preventive and lifestyle medicine and nutrition. He was not involved in the research.
“But they are also indicators of high fruit and vegetable intake, which is good for the brain because it is good for all vital organs, and the organism as a whole,” Katz said in an email. .
“They could also be indicators of better overall dietary quality, or better health awareness. Or maybe being more health conscious is a byproduct of better cognition.”
Plants contain over 5,000 flavonoid compounds that play a role. In generating cell proliferation, fighting environmental stress, and attracting insects for pollination.
Flavonols, a type of flavonoid, have been shown in animal and some human studies to reduce inflammation, a major trigger of chronic disease, and are a rich source of antioxidants. Antioxidants fight free radicals. Free radicals are “highly unstable molecules that form naturally when you exercise or when your body converts food into energy.” National Center for Complementary and Integrative Medicine, part of the National Institutes of Health.
One of the most common flavonols, quercetin, has been shown to be effective in reducing colorectal disease. cancer and other cancers, According to research. Onions contain the highest level — Lower levels are found in broccoli, blueberries, cauliflower, curly kale, chives, spinach and strawberries.
another common flavonol, Kaempferol, Supposed to suppress the growth of cancer cells Maintains and protects healthy cells. good source Kaempferol is mostly found in onions, asparagus, and berries, but the most abundant plant sources are spinach, kale, other green leafy vegetables, and herbs such as chives, dill, and tarragon.
A third major player is myricetin. studied in rodents Proteins responsible for glycemic control and tau reduction, characteristic tangles Alzheimer’s disease and other dementiasSpinach and strawberries contain high levels of myricetin, but honey, blackcurrants, grapes, other fruits, berries, vegetables, nuts and tea are also good sources.
The last group of flavonols, isorhamnetin, May protect against cardiovascular and neurovascular disease In addition to anti-tumor and anti-inflammatory benefits. Good sources of isorhamnetin are pears, olive oil, wine, and tomato sauce.
You can find a complete list of flavonoid content in various fruits and vegetables here.
A new study asked 961 people with an average age of 81 years and no signs of dementia to complete a food questionnaire each year for seven years. They were asked about the amount of time they spent physically and mentally.
People were divided into groups based on their daily intake of flavonols, with a minimum intake of approximately 5 milligrams per day. Studies point to up to 15 milligrams per day – equivalent to about 1 tablespoon of dark leafy greens. (For comparison, studies show that the average US adult intake of flavonols is about 16 to 20 milligrams per day.)
This study examined the effects of four major flavonols, kaempferol, quercetin, myricetin, and isorhamnetin, on rates of cognitive decline over a 7-year period.
The greatest effect was seen with kaempferol. The study found that those who ate the most foods containing kaempferol slowed cognitive decline by 0.4 units per decade compared to those who ate the least.
Myricetin followed. Those who ate the highest amount of myricetin-containing foods had a slower rate of cognitive decline of 0.3 units per decade compared to the lowest intake group. The rate of functional decline slowed by 0.2 units per decade.
The study found that dietary isorhamnetin had no effect.
Despite the apparent positive results, studies on the effects of flavonols on human health have been inconclusive. The main reason is that many are observational and cannot show direct cause and effect.
Several randomized controlled trials (scientific gold standards) have investigated type 2 diabetes and improve cardiovascular health, According to the Linus Pauling Institute,home Micronutrient Information Centeran online database of nutritional information.
It’s unclear whether these benefits are long-lasting, according to the lab, and no clear effects on cancer prevention or cognitive protection have been shown.
“There are other bioactive substances that may contribute to the observed results,” Katz said. “Supplementary studies are needed to fully isolate the effects of flavonoids.”
Dr. Christopher Gardner, a professor of medical research at Stanford University and director of the Nutrition Research Group, says there are downsides to making assumptions about health effects without the necessary research to support them.
“You can expect Americans to want the plant’s benefits but not want to eat it,” he said in an email.
“If people read the headlines and rush to buy bottled (extracted) flavonols instead of eating whole plant foods, and it’s not just flavonols, it’s the package deal for all of those plants. If it turns out (instead)
